a{
    text-decoration: none;/*去下划线*/
    color: #2b2f2f;
    background: cyan;
    width: 90px;
    height: 30px;
    display: inline-block;/*行级块标记*/
    text-align: center;
    line-height: 30px;/*设置为块的行高居中*/
    border-radius:5%;
    border :0px;
}
/*鼠标浮动效果*/
.btn:hover{
    background: #62ff00;
    color: black;
}